Ixvi THE BEGINNINGS OF LIFE. 



spring from Mosses. I again remark, we know so little of 

 the whole possible life-history of these simpler plants, that 

 our want of knowledge of a precedent cannot be quoted 

 against it/ 



Whilst such are the changes that take place in the 

 shade under the influence of warmth and moisture, the 

 growth of the cells is much checked during drought (espe- 

 cially in the summer) ; their walls become thickened, and the 

 chlorophyll utricles are more closely packed in their interior. 

 Drought also tends to produce a red or reddish -brown 

 colour in the cellulose wall of the cell. Filaments are often 

 (though not necessarily) in this condition when those peculiar 

 buds arise which constitute the first step in the growth of 

 a perfect Moss. This is one of the many modes of repro- 

 duction recognizable amongst these filaments. 



1. It takes place in the following manner : From 

 some one cell of the filament a branch is produced, and 

 after one or two dissepiments have been formed in it, 

 the terminal cell increases considerably in size. 'From 

 this/ Dr. Hicks 1 writes, 'many (three or four) branches 

 spring, in the mode of branching before mentioned, in a row 

 or vertical ; the cells of these branches are delicate and 

 tapering, and have the property of curving in towards the 

 centre. There is also a similar row of smaller branches 

 springing from the same cell within the former row, sur- 

 rounding as it were an imaginary axis. From this springs, 

 by gradual increment in the number of the cells, the stem 

 of the Moss. The first attempt at differentiation on the 

 part of the confervoid filament is thus shown to be in the 

 cell producing the rows of curving in branches/ 



2. The next mode of reproduction observable amongst 

 these confervoid filaments is also most prone to occur during 



1 L c- cit.p. 574. 



